Rear bumper for an automobile



FIG. 1 is a perspective view of a rear bumper for an automobile showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view; and,

FIG. 6 is a right side view thereof, the left side view being a mirror image. 

The ornamental design for a rear bumper for an automobile, as shown and described. 